Nice little game, shows a lot of potential, especially being your first game dev experience.
First I'm going to review the game as it is, as anything less will be a disservice to a budding game developer, but stick to the end for more praise. The game just has too little content. While the concept has a lot of potential, and the gameplay is mostly there, there is not a lot to do (which is understandable). The movement feels jagged, not at all smooth, which seems to come from the camera moving at integer pixel increments, this can be a valid choice, but I personally feel it makes moving in a straight line feel like going up or down steps. It can get monotonous as the targets appear in the same places, and even if they did not, getting them can be done with the same steps: point in the general direction and send the soul there, realize you were off course and adjust the mouse slightly. repeat. Finally, the lack of sounds can make everything dry.
Other than that, the visuals are excellent. Simple but consistent, monochromatic pixel art has more potential than some might think. The soul's sprite looks almost like a fireball, but the idea is there, and with minor tweaking could be so much better.
Now, to give some inspiration, the game could be improved by adding a simple story. Reading the description, I feel like something inspired by Return to the Obra Dinn, where the player finds sort of like memories of the past, could benefit the game greatly. Maybe write a story about this person and have it be revealed one piece at a time as you find this lights. One could bring a memory of the school they went to, a pet they used to love, their parents, siblings, lost ones. It could have a lot of the same gameplay, maybe with smaller additions like the terrain changing with every light found, or the soul being able to bounce and the player pushing it farther once out.
Overall, a good idea executed however you could, and it looks finished, even if there's so little to do. That's the greatest accomplishment starting game dev, actually finishing something no matter how simple. It shows potential for the future, and I hope I can see a game like this better fleshed out, because honestly I kinda want to play it.